If going out and spraying weed killer on weeds in your yard is too much of a hassle for you, why not get a friendly robot to do the dirty deed for you? Engineers at the University of Illinois have developed a solar powered robot that can search out weeds and then kill them with extreme prejudice. It utilizes GPS, robotic vision, and ultrasonic to find its way around your yard. When it finds a weed, it reaches out and slices it down with it's cutting arm, then sprays it with herbicide to get the job done. Trucking along at 3 MPH, it's a total killing machine. This guy isn't for sale, but perhaps if you promise to make a generous donation to the University of Illinois they'll let you borrow it once in a while.